<!DOCTYPE html>
<html>
<head>
	<title></title>
	<style type="text/css">
		#out {
			/*width: 80%;*/
			height: 200px;
			background-color: red;
			margin: 10px auto;
			padding: 10px;
		}
		.left {
			width: 500px;
			height: 100px;
			background-color: green;
			float: left;
		}
		.right {
			width: 500px;
			height: 100px;
			background-color: yellow;
			float: right;
		}
	</style>
	<script type="text/javascript">
  // 宽
		window.onload = function(){
			var out = document.getElementById('out');
			out.style.width = screen.availWidth+"px";
      console.log(out.style.width);
		}
    // 高
    window.onload = function(){
			var out = document.getElementsByClassName("cesium-widget")
			out.style.height = screen.availHeight+"px";
		}
	</script>
</head>
<body>
	<div id="out">
		<div class="left"></div>
		<div class="right"></div>
	</div>
</body>
</html>
